543728-65-0Relevant academic research and scientific papers
Structure and dynamics of half-sandwich ruthenium(IV) alkynyl hydrido complexes
Aneetha, Halikhedkar,Jimenez-Tenorio, Manuel,Puerta, M. Carmen,Valerga, Pedro,Mereiter, Kurt
, p. 2001 - 2013 (2008/10/08)
The coordinatively unsaturated complex [Cp*Ru(PMeiPr2)2][BAr′4] (1; BAr′4 = B{3,5-C6H3- (CF3)2}4) reacts 1-alkynes in diethyl ether at 0°C, furnishing the RuIV alkynyl hydrido derivatives [Cp*RuH(C≡CR)(PMeiPr2)2] [BAr′4]. In an analogous fashion, the reaction of 1 with 1-alkyn-3-ols in diethyl ether at 0 °C leads to the 3-hydroxyalkynyl hydrido complexes [Cp*RuH(C≡CC(OH)RR′)(PMei Pr2)2][BAr′4]. The complexes [Cp*RuH(C≡CCOOMe)(PMeiPr2)2] [BAr′4] and [Cp*RuH(C≡CC(OH)Ph2) (PMeiPr2)2][BAr′4]· Et2O have been structurally characterized, and their crystal structures show a transoid disposition of the hydride and alkynyl ligands. These compounds are stereochemically nonrigid and undergo a rapid equilibrium between possible stereoisomers in solution, which has been studied by variable-temperature NMR spectroscopy and computer simulation. The dynamic NMR study for these processes indicates energy barriers of ca. 11 kcal mol-1, and moreover the differences in energy for the possible stereoisomers are very small (ca. 1 kcal mol-1). The akynyl hydrido complexes rearrange to their more stable vinylidene or hydroxyvinylidene tautomers. Spontaneous dehydration of the latter leads to either vinylvinylidene or allenylidene complexes.
